U.S. President Barack Obama says he is "deeply concerned" about the detention and expulsion of Honduran President Jose Manuel Zelaya by Honduran soldiers.

President Obama said the situation must be resolved peacefully through negotiations free from any outside interference. He called on all sides in Honduras to respect democratic norms and the rule of law.

U.S. Secretary of State Hillary Clinton said the actions taken against Mr. Zelaya should be condemned by all.

Venezuelan President Hugo Chavez denounced Mr. Zelaya's arrest, and according to the French news agency (AFP), suggested the United States may have played a role - an allegation quickly rejected by the White House.

Mr. Chavez said he put his troops on alert and threatened military action if the Venezuelan ambassador to Honduras is harmed.

The Organization of American States is holding an emergency meeting in Washington Sunday on the Honduran situation.

The European Union was also quick to condemn the military's action against the Honduran president. The EU called for Mr. Zelaya's urgent release and a swift return to constitutional normality.

Honduran soldiers arrested Mr. Zelaya early Sunday at his home. He later arrived in Costa Rica.

The Honduran president was detained shortly before voting was to start in a referendum on changing the constitution to allow him to run for another term.

Mr. Zelaya had insisted on holding the referendum even though the Honduran Supreme Court ruled it illegal.